Manufacture of screws.



W. G. ALLEN. MANUFACTURE OF SGEEWS.

APPLICATION FILED JAN. 9, 1909.

60,244. Patented June 7; 1910.

WILLIAM G. ALLEN, OF WEST HARTFORD, CONNECTICUT, ASSIGNOR OF ONE-HALF TOIRA. DIMOGK, OF WEST HARTFORD, COIhlNECTICUT.

MANUFACTURE OF SCREWS.

To all whom it may concern.

Be it known that I, WILLIAM G. ALLEN, a citizeh of the United States,residing at -West Hartford, in the county of Hartford and State ofConnecticut, have invented a new and useful Improvement in Manufactureof Screws, of which the following is a specification. 1

This invention relates more particularly to the manufacture of flushhead set screws, that is, set'screws so shaped and threaded that whenput to use their hcads are sunk even with the outer surfaces of the artsinto which they are driven, although t e invention'is applicable to themanufacture of machine screws and set screws having projecting orfillister heads.

t is inow generally recognized as very desirable, and numerousgovernments, State and national, make it obligator for the purpose ofeliminatin due to projecting hea s of set screws on r0- tating parts, toeither protect such heads of screws on rotating parts by a cover orguard,

or to sink the heads flush with the rotating surface, and for thispurpose screws having hollow heads, adapted to receive a key or crankfor turning them in are proposed.

The object of this invention is the production of machine screws,particularly set screws, which are very simple and cheapto make, in factcheaper than the common headed set screws, which can be entirely sunkbelow the surface of the rotating parts into which they are screwed, andwhich are very strong and consequently can be set tightly and will holdfirmly.

The invention is applicable to the production of many types of screws ofany length and any diameter from common screw rod,

for instance either short or long screws that are threaded their entirelength or only a part of their length by either rolled or cut.

threads, and screws of any size which are the same diameter throughouttheir length, or have enlarged heads if desired, which screws can beformed by various steps. The result obtained by the practice of myinvention is a screw having a 'substantlal body portion with suflicientmetal'to insure strong,

with an angular or non-cirperfect threads,

surrounded by a cular socket in the head,

substantial body of firm metal, which socket Specification of LettersPatent. Application filed January 9, 1909. Serial No. 471,400.

.is designed to receive a danger o accidents.

Patented June '17, 1am.

strong key or crank end for turning the screw in or out of its desiredposition.

Figure 1 of the accompanying drawings shows a series of viewsillustrating one method of producing set screws which embody thisinvention. Fig. 2 shows a series of views illustrating a similar methodof producing such screws. Fig. 3 shows another method. Fig. 4illustrates a method of producing a headed machine screw which embodiesthe invention. Fig. 5 illustrates another method.

Referring to the steps employed in pro-' ducing the screws illustratedby Fig. 1, a piece of suitable round wire stock of any diameter andlength is cut to form a blank, 1, and one end upset in the ordinary wayto fornran expanded head 2 in a common header or rivet forming 'machine.This blank is then driven through a die 3 of ordinary form by a punch 4,which is preferably hexagonal in cross section, although of course itmight be square or have any desired shape other than round. Thisoperation causes the expanded head .of the blank to be drawn up to theoriginal diameter of the wire, leaving a socket 5 in the end having thesame cross-sectional shape as the punch. The blank thus formed may bethreaded for any desired part of its length, as is the screw 6, or forits entire length, as is the screw 7, by either cutting the threads orby rolling the threads in the common manner, If the screw is to bethreaded for only a part of its length, the threads" could of course beformed by cutting or rolling before the headed blank is punched throughthe die to draw up the end.

Referring to F ig. 2, the blank 8 may be formed of any ordinary roundstock of suitable length and diameter and swaged or punched to providean enlarged head 9. This blank with the head slightly larger in diameterthan the body of the blank and containing the circular drilled orpunched socket 10 may then be driven by a punch 11 through a die 12 toreduce and draw the head to the original diameter and form the socket 13of angular or non-circular cross section. Such a blank can be threadedfor a part of its length to form the screw 14, or for its entire length,as is the screw 114:, by cutting or rollin' the threads either before orafter the hea is drawn to form the socket in the head end.

. Instead of forming the enlarged head of the blank by swaging orupsetting its end if desired, a blank of round stock 0 suitable lengthand diameter can be turned down to form a blank 16 with an enlargedhead. This head is then drilled to form a socket 17. Such a blank maythen be punched through a die, as previously described, by a punchhaving the desired cross sectional shape, so as to draw up the head andform the blank 18 with the angular or non-circular socket 19. Such ablank may then be threaded by rolling or cutting the threads for a partof or its entire length in the usual way, or may be left without threadsfor future treatment.

To form a machine screw with an enlarged head, a blank may be swaged orturned to the shape of the blank 20 shown in Fig. 4:. This blank withits head 21 slightly larger than the finished head ofthe 22 drilledinit,'is

screwzls to be, and having a circular socket punched through a die 23'by'a' punch 24, an the head drawn to final shape,'as is the head 25with the angular socket 26'. The shank 27 of this screw may be threadedby rollingor cutting, either before or after the head is formed to finalshape.

As rolling a thread. increases the diameter of the stock, that is, thefinished screw is larger in diameter than the rod before the thread wasrolled, the practice of this invention may be carried on by taking aheaded blank 28 with a perforation 29 therein, and punching it through adie producing a blank 30, with a head slightly larger in diameter thanthe shank. This head is of the size of the finished screw, then when thethread is rolled the completed-screw 3'15. will be of uniform diameterthroughout its length. a

By the practice of this invention, screws of any length and any diameterwith or without enlarged heads and threaded for their entire or only apart of their length by rolling or cutting, can be rapidly produced withangular. or non-circular sockets in the head end without redrawing toincrease their length. Such sockets can be 'more quickly andcheaply-formed than slots can be cut in the ordinary screws, and theyare accurate in shape and size. Screws produced in this manner,'asstated, can be any length and diameter and can be formed of ordinaryround, stock in such manner that the threads can be perfectly formed in.a body that has sufficient metal to bestron and substantial. Thesockets are formed quickly in the head ends and the metal about thesockets is firm and substantial, in fact 'tion.

the head is stronger than when slotted, so

that a strong key or crank end can be inserted for turning the screws'inor out, without danger of breaking the head ends of the the screws maybe turned in or out by a. key or crank. )The same size and depth ofsocket can be made in screws having the same diameter and rapidly madeare very strong, both along the shanks and at the head ends and whenheaded screws are made the under regardless of their -len h, which is asavlng of labor in their pr uc- These screws which are so cheaply,

side of the heads are flat and the corners square.

The invention claimed 1s."

1. The process of making a socketed machine screw, which consists inproviding a solid cylindrical blank of metal with an enlargement at oneend, forming a socket in Y the enlarged end, forcing the blank by anangular or non-circular punch through a die opening that is smaller indiameter than theenlarged end of the blank, thereby causing a reductionin the exterior diameter of the enlarged end and compressing that endonto the punch and producing an angular ornon-circular socket therein,and forming a' thread upon the exterior of the blank.

2. The process of making a socketed machine screw, which consists inproviding a solid blank of metal with an enlargement at one end,punching or drilling a circular blank by an angular or non-circularpunch through a die opening that is smaller 1n diameter than theenlarged end of the blank, thereby causing a reduction in the exterior.diameter of the enlarged end and compressing that end onto the punch andchanging the socket from circular to angular or noncircular incross-section, an forming a screw thread upon the exterior of the blank.

3. The process of making a socketed blank, which consists in providing asol d piece of metal with an enlargement at one end, forming a socket inthe enlarged end, and forcing the blank by an angular or nonsocket inthe enlarged end, forcing the circular punch through a die opening thati is smaller in diameter than the enlarged end of the blank, therebycausing a reduction in and pro ucing an angular or non-circular sockettherein.

Witnemes:

HARRY R. WILLIAMS, v Josnrmnr. M. STREMPFER.

WILLIAM G. ALLEN.

